I recently had a tune up done on my '95 Suburban (165k)...the mechanic said that the old plugs were not the right ones and that he replaced the plugs with oem spec plugs...the truck now runs worse than ever. I took it back and they found a cracked plug and replaced it. 1000 miles later and the truck is doing the same thing...missing real bad at idle. I took it back to the mechanic and told him it was doing the same thing as when the cracked plug issue surfaced. He did not look at the plugs but said I needed a new egr valve. I took it somewhere else and that mechanic said it sounded to him like I needed new plugs. When the truck misses, the tach stays at tyhe same level...does not dip at all

So a couple questions...what type of plugs do you like for this truck, and does this sound like a plug problem or could it be the egr valve?

thanks

 

could be either one of those, or something else. with the computer systems, you need to stay with stock plugs. did mechanic actually change the cap, rotor, wires, and filters too? these are all part of a standard tune-up. as much as we want to believe people, some do fib. does 'burb run rough all the time, just at idle, at highway speeds?

 

The mechanic replaced the wires for sure, and the fuel filter (so he says). I have no reason to doubt that he did. as to the cap and rotor, I thought this 'burb was all electric ignition...

 

'95 still has cap/rotor. the ignition and timing are all electronic. dirty fuel filter can cause issues.

 

Stick with AC Delco plugs gapped at .035"
You didn't answer maxxman's question about your miss, is it only at idle, at speed or under load. Could be the egr or a vacuum leak.

 

oh yes, sorry...

the miss is mostly at idle, truck in gear, foot on brake. It does not miss with the truck in park. Every now and then the miss will appear for a brief split second at highway speed. It is mostly though at idle like sitting at a stop light.

The cel comes on for a while sometimes on highway, but then will shut back off.

 

it's a good possibility the egr is clogged. most of the time you can take it off, clean the carbon out of it, and put it back on. it is highly recommended that you replace the egr gasket with a new one that has a screen on it. that screen will help keep carbon from building up in it again.

 

ok..thanks...I will remove the egr valve and clean it...I am guessing that carb cleaner should work fine?

thanks

 

any idea who makes a gasket like this, & (possibly) a part number?? Checking out NAPA's site, I only see gaskets that are open...no screen....